Homework #5 1040

1.       1. Use Python to create three rotation curve diagrams as shown in class. They should have distance on the x-axis and velocity on the y-axis. Axes must be labelled. Each should have a title created in Python.

a.       A rigid rotator.  Plot the velocity of rotation in km/s of 100 points spaced evenly along a stick that is 30AU long and rotates once per year.

b.       The Solar System. Read the file SolarSystem.txt that was provided, using numpy.loadtext. Plot the data as you did in part a.

c.       The Milky Way. Read the file milkyway.txt and create a third plot.

d.  Explain in general terms why the three charts have such different shapes.

2.       2. Create your own spiral galaxy (as was shown in class) using powerpoint.  (Powerpoint is the most commonly used diagram package and it is worth knowing if you don’t already.)  Create a series of ten ellipses of increasing size, but same eccentricity. Put them all on a common center. Rotate the major axis of each ellipse a little more with each increase in size to create a spiral.  Do the same thing again with more change in angle between each ellipse.  Do the same thing again, but increase the eccentricity of each ellipse.  Can you conclude anything about the creation of the different kinds of spiral galaxies?

3.       3. Use powerpoint as a diagram generator.  Draw an edge on view of a spiral galaxy just like the ppt I showed in lecture using standard ppt shapes. Label the various parts of the galaxy and the position of the Sun.  (Again, this is just an exercise in powerpoint, more than astronomy.)